Their ages weren't available, and they were summoned to appear in court later to answer to the charges.

Their cases are spinoffs from an investigation in 2010 and 2011 by the FBI and IRS in which eight other people were prosecuted, including the two main targets who took their own lives as they still were being prosecuted.

Those contractors, David J. Reitman, 52, and Gary Schwing, 65, admitted to a scheme to give some ex-Zachry Industrial managers kickbacks so they would inflate invoices and cause the San Antonio company to overpay $10 million.

For seven years until 2010, the then-Zachry employees inflated invoices to pay the company for tools and supplies that were never delivered, that previous case established.

Thomas, Holder and Perez had lesser involvement in the fraud, according to their indictments.

According to their indictments, Thomas got $57,600 in kickbacks from his accomplices, Holder got $47,000 and Perez got $40,000.

Perez had worked for Zachry on and off beginning in 1990, in warehouse areas at various sites.

He was fired in July 2010, the indictment said. Thomas was a quality control manager from 2009 until he was fired in fall 2010. Holder was a purchasing agent and had worked for Zachry from 1979 through 2009, but the indictment does not say whether he was fired.

In the prior prosecution, amid plea negotiations, Schwing was found dead in October 2011 at his Sugar Land home. While awaiting sentencing, Reitman took his own life at a Houston hotel a few weeks after that.

Six others, five of them ex-Zachry employees, pleaded guilty for their roles. They received sentences ranging from five years of probation to four years in prison and orders to pay $61,038 to $3.5 million.